Federal mandates to increase biofuel production in North America will require large new tracts of land with potential to negatively impact biodiversity, yet empirical information to guide implementation is limited. Because the temperate grassland biome will be a production hotspot for many candidate feedstocks, production is likely to impact grassland birds, a group of major conservation concern. We employed a multiscaled approach to investigate the relative importance of arthropod food availability, microhabitat structure, patch size and landscape-scale habitat structure and composition as factors shaping avian richness and abundance in fields of one contemporary (corn) and two candidate cellulosic biomass feedstocks (switchgrass and mixed-grass prairie) not currently managed as crops. Bird species richness and species density increased with patch size in prairie and switchgrass, but not in corn, and was lower in landscapes with higher forest cover. Perennial plantings supported greater diversity and biomass of arthropods, an important food for land birds, but neither metric was important in explaining variation in the avian community. Avian richness was higher in perennial plantings with greater forb content and a more diverse vegetation structure. Maximum bird species richness was commonly found in fields of intermediate vegetation density and grassland specialists were more likely to occur in prairies. Our results suggest that, in contrast to corn, perennial biomass feedstocks have potential to provide benefits to grassland bird populations if they are cultivated in large patches within relatively unforested landscapes. Ultimately, genetic improvement of feedstock genets and crop management techniques that attempt to maximize biomass production and simplify crop vegetation structure will be likely to reduce the value of perennial biomass plantings to grassland bird populations.
Increased production of biomass crops in North America will require new agricultural land, intensify the cultivation of land already under production and introduce new types of biomass crops. Assessing the potential biodiversity impacts of novel agricultural systems is fundamental to the maintenance of biodiversity in agricultural landscapes, yet the consequences of expanded biomass production remain unclear. We evaluate the ability of two candidate second generation biomass feedstocks (switchgrass, Panicum virgatum, and mixed-grass prairie) not currently managed as crops to act as post-breeding and fall migratory stopover habitat for birds. In total, we detected 41 bird species, including grassland specialists and species of state and national conservation concern (e.g. Henslow's Sparrow, Ammodramus henslowii). Avian species richness was generally comparable in switchgrass and prairie and increased with patch size in both patch types. Grassland specialists were less abundant and less likely to occur in patches within highly forested landscapes and were more common and likely to occur in larger patches, indicating that this group is also area-sensitive outside of the breeding season. Variation in the biomass and richness of arthropod food within patches was generally unrelated to richness and abundance metrics. Total bird abundance and that of grassland specialists was higher in patches with greater vegetation structural heterogeneity. Collectively, we find that perennial biomass feedstocks have potential to provide post-breeding and migratory stopover habitat for birds, but that the placement and management of crops will be critical factors in determining their suitability for species of conservation concern. Industrialization of cellulosic bioenergy production that results in reduced crop structural heterogeneity is likely to dramatically reduce the suitability of perennial biomass crops for birds.
New forest policies in South Africa seek to reconcile conservation and development objectives by devolving some responsibility for forest management from the state to local communities. Community participation in forest management aims to protect forest-based subsistence livelihoods by incorporating the interests of resource users, while simultaneously diffusing threats to biodiversity by managing resource use. To date, participatory forest management (PFM) has had mixed success in South Africa because the transfer of rights to users has not accompanied changes in policy. A questionnaire survey of 60 households (43%) revealed the attitudes of users toward current management and conservation options for iGxalingenwa forest. Users chose participatory forest management (52%) over community (25%) or state-dominated forest management (2%) structures. User choice was motivated by the desire to secure rights of access to, and ensure equitable benefit from, a dwindling resource base, rather than the conservation of these resources to sustain future yields. Users were unwilling to reduce resource use and compromise usufruct rights to achieve conservation goals, even to improve the availability of the resource stock. Current user needs compromise biodiversity conservation goals, and users regard state conservation practices as protectionist and obstructing their rights of access to resources. While the National Forests Act of 1998 seeks to conserve resources by limiting access to them and is based on principles of sustainable use, it is nevertheless perceived to offer few incentives to users to participate in forest management and conservation. Ideally, an institutional and legal framework that allocates user rights and managerial responsibilities to households is required, but clearly suitable alternatives to forest products are also vital for successful management. Greater trust between the provincial parks authority and users is needed, but is complicated by weak traditional leadership and poor community representation. Ultimately, users preferred PFM because, while recognizing that harvest rates are unsustainable, user dependence upon forest resources and weak traditional leadership means they can protect usufruct rights only by participation. Changes to any of these factors may create demands for a new management system. PFM allows the greatest flexibility for responding to changes in demands as well as the environment.
‘Educational supervisor’ is the term now used by the General Medical Council for a consultant who has junior doctors working with him/her, whether employed by the National Health Service or a university. This paper represents our views of the role of the educational supervisor, rather than official College policy.
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